There was one particular turn of phrase that sparked something of a maelstrom on Twitter during Donald Trump's inaugural address.

As Trump was describing families trapped in poverty, rusted-out factories, an education system "flushed with cash" but failing students, and crime and gangs and drugs, he backed it up with this line.

“This American carnage stops right here and stops right now," he said.

"American carnage" immediately became a thing.